gadahl Okay, I think I see part of the confusion, the label on the bag for the Blue Ribbon Maple Bacon Cure says “Use 2 lb of cure to 100 lb of fresh bellies. This imparts 120 ppm of nitrite and 547 ppm of erythorbate” As the bags have 5 lb of cure this means you would get 2.5 batches out of each bag and each batch does 100 lb of meat so it is enough to cure 250 lb of bellies.
If you are looking at a bag and it says something other than “Use 2 lb of cure to 100 of fresh bellies” please let me know!
As for the math at the end of your post, you wouldn’t use 5 lb of cure to 5 gallons of water, you would use 5 lb of cure to 2.5 gallons of water. Each gallon weighs 8.34 lb so 2.5 x 8.34 = 20.85 (water), 20.85 + 5 lb (cure) = 25.85 and with that you could pump 250 lb of fresh bellies.
Let me know if I did not understand something correctly!